Pipes that are used to carry liquid are subject to damage do to freezing. A variety of methods have been employed to prevent this from happening. One such method is to wrap electric wire around the pipe. The wire conducts current when the pipe gets near a freezing temperature. The disadvantages of this method include installation and electrical energy consumption. Other methods require installation of special valves and/or other mechanical plumbing devices. The disadvantages of these alternatives are the cost of the additional devices and required installation.
Many times the pipes needing protection are part of a heating system which heats a zone by passing water heated in a boiler to a designated zone through pipes. If the pipes pass through an unusually cold area and/or if the heated zone is not calling for heat the pipes may freeze. Providing a device which commands hot water or any liquid to flow before freezing occurs will prevent freezing from occurring.